Organic light-emitting display having light blocking layer formed over pixel defining layer

ABSTRACT

An organic light-emitting display includes a substrate including a pixel region and a transistor region; a first transparent electrode and a second transparent electrode formed over the pixel region and the transistor region of the substrate, respectively; a gate electrode formed over the second transparent electrode; a gate insulating film formed over the gate electrode; a semiconductor layer formed over the gate insulating film; a source and drain electrode having an end connected to the semiconductor layer and the other end connected to the first transparent electrode; a pixel defining layer disposed over the source and drain electrode to cover the source and drain electrode and having an opening disposed over the first transparent electrode; a light-blocking layer formed over the pixel defining layer; and an organic light-emitting layer formed over the first transparent electrode.

This application is a divisional of U.S. patent application Ser. No.13/349,398, filed Jan. 12, 2012, which claims priority to Korean PatentApplication No. 10-2011-0014717 filed on Feb. 18, 2011 in the KoreanIntellectual Property Office. The disclosures of the U.S. patentapplication Ser. No. 13/349,398 and the Korean Patent Application No.10-2011-0014717 are incorporated herein by reference in their entirety.

BACKGROUND

1. Field

The present disclosure relates to an organic light-emitting display anda method of manufacturing the same, and more particularly, to reducingdeterioration of organic light-emitting displays caused by light.

2. Description of the Related Technology

Generally, in an active matrix organic light-emitting diode (AMOLED)panel, light is generated by supplying currents to an organiclight-emitting diode (OLED) which is a self-luminous device.

For example, in an organic light-emitting display using an OLED, a gateelectrode, a semiconductor layer, and a source and drain electrode aresequentially formed on a substrate, and a pixel defining layer is formedto cover the resultant structure. If the organic light-emitting displayis of a bottom emission type, light emitted from the OLED of a pixelregion exits the organic light-emitting display via the substrate.

However, when the OLED continuously emits light for a certain period oftime, even if the same current is supplied to the OLED, the amount oflight that the OLED emits decreases over time, or the number ofmalfunctions increases over time. As a result, the reliability of theOLED is undermined.

Such a problem occurs particularly when an oxide semiconductor sensitiveto moisture and heat is used in the organic light-emitting displaybecause the oxide semiconductor is degraded by light emitted from theOLED and thus its optical reliability is deteriorated.

Therefore, it is required to minimize reliability deterioration of theoxide semiconductor resulting from the degradation of the oxidesemiconductor by light emitted from the OLED.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

Aspects of the present invention provide an organic light-emittingdisplay and a method of manufacturing the same, in which degradation ofan oxide semiconductor layer by light is minimized to improve theelemental reliability of the oxide semiconductor layer.

Aspects of the present invention also provide an organic light-emittingdisplay and a method of manufacturing the same, in which alight-blocking layer having a light-blocking effect is further formedover a pixel defining layer to improve the elemental reliability of anoxide semiconductor layer.

However, aspects of the present invention are not restricted to the oneset forth herein. The above and other aspects of the present inventionwill become more apparent to one of ordinary skill in the art to whichthe present invention pertains by referencing the detailed descriptionof the present invention given below.

According to an aspect of the present invention, there is provided anorganic light-emitting display comprising: a substrate comprising apixel region and a transistor region; a first transparent electrode anda second transparent electrode formed over the pixel region and thetransistor region of the substrate, respectively; a gate electrodeformed over the second transparent electrode; a gate insulating filmformed over the gate electrode; a semiconductor layer formed over thegate insulating film; a source and drain electrode comprising an endconnected to the semiconductor layer and the other end connected to thefirst transparent electrode; a pixel defining layer disposed over thesource and drain electrode to cover the source and drain electrode andcomprising an opening disposed over the first transparent electrode; alight-blocking layer formed over the pixel defining layer; and anorganic light-emitting layer formed over the first transparentelectrode.

According to another aspect of the present invention, there is providedan organic light-emitting display comprising: a substrate comprising apixel region and a transistor region; a first transparent electrode anda second transparent electrode formed over the pixel region and thetransistor region of the substrate, respectively; a gate electrodeformed over the second transparent electrode; a gate insulating filmformed over the gate electrode; a semiconductor layer formed over thegate insulating film; a source and drain electrode comprising an endconnected to the semiconductor layer and the other end connected to thefirst transparent electrode; a first pixel defining layer disposed overthe source and drain electrode to cover the source and drain electrodeand comprising an opening disposed the first transparent electrode; alight-blocking layer formed over the first pixel defining layer; asecond pixel defining layer formed over the first pixel defining layerand the light-blocking layer, wherein the light-blocking layer isinterposed between the first and second pixel defining layers; and anorganic light-emitting layer formed over the first transparentelectrode, wherein the light-blocking layer comprises an openingdisposed over the first transparent electrode, wherein the boundary ofthe opening of the light-blocking layer is situated further away fromthe center of the opening of the first pixel defining layer than theboundary of the opening of the first pixel defining layer.

According to another aspect of the present invention, there is provideda method of manufacturing an organic light-emitting display, the methodcomprising: forming a first transparent electrode and a secondtransparent electrode over a pixel region and a transistor region of asubstrate, respectively; forming a gate electrode over the secondtransparent electrode; forming a semiconductor layer over the transistorregion; forming a source and drain electrode, which comprises an endconnected to the semiconductor layer and the other end connected to thefirst transparent electrode, over the semiconductor layer; forming apixel defining layer over the source and drain electrode to cover thesource and drain electrode; forming an open portion, which exposes thefirst transparent electrode of the pixel region, in the pixel defininglayer; forming a light-blocking layer over the pixel defining layer; andforming an organic light-emitting layer over the first transparentelectrode.

According to another aspect of the present invention, there is provideda method of manufacturing an organic light-emitting display, the methodcomprising: forming a first transparent electrode and a secondtransparent electrode over a pixel region and a transistor region of asubstrate, respectively; forming a gate electrode over the secondtransparent electrode; forming a semiconductor layer over the transistorregion; forming a source and drain electrode, which comprises an endconnected to the semiconductor layer and the other end connected to thefirst transparent electrode, over the semiconductor layer; forming afirst pixel defining layer over the source and drain electrode to coverthe source and drain electrode; forming an open portion, which exposesthe first transparent electrode of the pixel region, in the first pixeldefining layer; forming a light-blocking layer over the first pixeldefining layer; forming a second pixel defining layer over the firstpixel defining layer and the light-blocking layer wherein thelight-blocking layer is interposed between the first and second pixeldefining layers; and forming an organic light-emitting layer over thefirst transparent electrode, wherein the light-blocking layer comprisesan opening disposed over the first transparent electrode, wherein theboundary of the opening of the light-blocking layer is situated furtheraway from the center of the opening of the first pixel defining layerthan the boundary of the opening of the first pixel defining layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects and features of the present invention willbecome more apparent by describing in detail embodiments thereof withreference to the attached drawings, in which:

FIG. 1 is a schematic cross-sectional view of an example of an organiclight-emitting display;

FIG. 2 is a schematic cross-sectional view of an organic light-emittingdisplay according to an embodiment of the present invention;

FIGS. 3 through 9 are cross-sectional views sequentially illustrating amethod of manufacturing an organic light-emitting display according toan embodiment of the present invention;

FIG. 10 is a flowchart illustrating a process of forming a pixeldefining layer and a light-blocking layer in an organic light-emittingdisplay according to an embodiment of the present invention;

FIG. 11 is a schematic cross-sectional view of an organic light-emittingdisplay according to another embodiment of the present invention;

FIGS. 12 through 14 are cross-sectional views sequentially illustratinga method of manufacturing an organic light-emitting display according toanother embodiment of the present invention; and

FIG. 15 is a flowchart illustrating a process of forming first andsecond pixel defining layers and a light-blocking layer in an organiclight-emitting display according to another embodiment of the presentinvention.

DETAILED DESCRIPTION OF CERTAIN INVENTIVE EMBODIMENTS

Advantages and features of the present invention and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of embodiments and the accompanyingdrawings. The present invention may, however, be embodied in manydifferent forms and should not be construed as being limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete and will fully conveythe concept of the invention to those skilled in the art, and thepresent invention will only be defined by the appended claims. In thedrawings, sizes and relative sizes of layers and regions may beexaggerated for clarity.

It will be understood that when an element or layer is referred to asbeing “on” another element or layer, the element or layer can bedirectly on another element or layer or intervening elements or layersmay also be present. In contrast, when an element is referred to asbeing “directly on” another element or layer, there are no interveningelements or layers present. As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.

Spatially relative terms, such as “below”, “beneath”, “lower”, “above”,“upper”, and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation, in addition to theorientation depicted in the figures. Like reference numerals refer tolike elements throughout the specification.

Embodiments of the invention are described herein with reference to planand cross-section illustrations that are schematic illustrations ofidealized embodiments of the invention. As such, variations from theshapes of the illustrations as a result, for example, of manufacturingtechniques and/or tolerances, are to be expected. Thus, embodiments ofthe invention should not be construed as limited to the particularshapes of regions illustrated herein but are to include deviations inshapes that result, for example, from manufacturing. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the actual shape of a region of a device andare not intended to limit the scope of the invention.

Hereinafter, an organic light-emitting display according to anembodiment of the present invention will be described with reference toFIG. 2. FIG. 2 is a schematic cross-sectional view of an organiclight-emitting display according to an embodiment of the presentinvention.

The organic light-emitting display according to the current embodimentincludes a substrate 10 having a pixel region P, a transistor region Tand a capacitor region C, a transparent electrode 12 formed on each ofthe pixel region P, the transistor region T and the capacitor region Cof the substrate 10, a gate electrode 14 formed on the transparentelectrode 12, a gate insulating film 16 formed on the gate electrode 14,a semiconductor layer 18 formed on the gate insulating film 16 of thetransistor region T, a source and drain electrode 24 having an endconnected to the semiconductor layer 18 and the other end connected tothe transparent electrode 12 of the pixel region P, a pixel defininglayer 26 disposed on the source and drain electrode 24 to cover thesource and drain electrode 24 and having an open portion O which exposesthe transparent electrode 12 of the pixel region P to define the pixelregion P, a light-blocking layer 28 formed on the pixel defining layer26 in the same pattern as the pixel defining layer 26, and an organiclight-emitting layer formed on the transparent electrode 12 of the pixelregion P.

The substrate 10 may be made of a transparent glass material containingSiO2 as a main component. However, the material that forms the substrate10 is not limited to the transparent glass material. The substrate 10may also be made of a transparent plastic material. If the organiclight-emitting display according to the current embodiment is a bottomemission organic light-emitting display, light emitted from the organiclight-emitting layer exits the organic light-emitting display throughthe substrate 10. Therefore, the substrate 10 should be made of atransparent material in order to not block the light. However, if theorganic light-emitting display according to the current embodiment is atop emission organic light-emitting display, the substrate 10 may notnecessarily be made of a transparent material.

The plastic material that forms the substrate 10 may be an insulatingorganic material selected from the group consisting of polyethersulphone(PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene napthalate(PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS),polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC),and cellulose acetate propionate (CAP).

The substrate 10 included in the organic light-emitting displayaccording to the current embodiment may be partitioned into the pixelregion P, the transistor region T, and the capacitor region C. The pixelregion P is a region on which the organic light-emitting layer is formedto emit light, and the transistor region T controls a voltage flowing tothe pixel region P. In addition, the capacitor region C enables avoltage to remain constant without dropping between frame signals.

A buffer layer (not shown) may further be formed on the substrate 10 toplanarize the substrate 10 and prevent penetration of impurities intothe substrate 10. The buffer layer may be a single layer of SiOx, SiNxor SiO2Nx, or a multilayer of these materials. The buffer layer may beformed by chemical vapor deposition (CVD) or physical vapor deposition(PVD).

The transparent electrode 12 is formed on each of the pixel region P,the transistor region T and the capacitor region C of the substrate 10.If the organic light-emitting display according to the currentembodiment is a bottom emission organic light-emitting display, sincelight exits the organic light-emitting display via the transparentelectrode 12 and the substrate 10, the transparent electrode 12 may bemade of a transparent material, i.e., a transparent conductive material.The transparent conductive material may be a mixture of one or morematerials selected from indium tin oxide (ITO), indium zinc oxide (IZO),carbon nanotubes, a conductive polymer, and nanowires.

A voltage applied to the source and drain electrode 24 by thesemiconductor layer 18 is delivered to the transparent electrode 12 ofthe pixel region P, causing the organic light-emitting layer disposed onthe transparent electrode 12 to emit light by itself.

The gate electrode 14 may be formed on the transparent electrode 12 ofeach of the transistor region T and the capacitor region C. A gatevoltage is applied to the gate electrode 14, and the gate electrode 14may be a single layer of Al or an Al alloy, such as Al—Nd, or amultilayer of a Cr or Mo alloy and an Al alloy stacked on the Cr or Moalloy.

The gate insulating film 16 is disposed on the gate electrode 14. Likethe buffer layer described above, the gate insulating film 16 may be asingle layer of SiO₂, SiN_(X) or SiO2Nx, or a multilayer of thesematerials. The gate insulating film 16 may be made of the same materialas the buffer layer or a different material from that of the bufferlayer.

As will be described later, the gate insulating film 16 is coated on theentire surface of the substrate 10, and the open portion O exposing thetransparent electrode 12 of the pixel region P is formed on a portion ofthe pixel region P on which the organic light-emitting layer isprovided.

The semiconductor layer 18 is provided on the gate insulating film 16 ofthe transistor region T. The semiconductor layer 18 may control acurrent supplied to the transparent electrode 12 of the pixel region Pby selectively supplying a current to the source and drain electrode 24.

The semiconductor layer 18 may be made of silicon (Si), i.e., amorphoussilicon (a-Si). Alternatively, the semiconductor layer 18 may be made ofpolycrystalline silicon (p-Si), depending on the amount of currentrequired. Otherwise, the semiconductor layer 18 may be made of, but isnot limited to, Ge, GaP, GaAs, or AlAs.

In particular, the semiconductor layer 18 according to the currentembodiment may be an oxide semiconductor layer made of an oxide. Forexample, the semiconductor layer 18 may contain an oxide of a materialselected from Zn, In, Ga, Sn, Hf, and a combination of the same. Thatis, the semiconductor layer 18 may be made of a mixed oxide selectedfrom ZnO, InZnO, InGaO, InSnO, ZnSnO, GaSnO, GaZnO, GaZnSnO, andGaInZnO. The oxide semiconductor layer 18 has 2 to 100 times greatereffective charge mobility than amorphous silicon and has an on/offcurrent ratio of 10⁵ to 10⁸. Thus, the oxide semiconductor layer 18shows excellent semiconductor properties.

Furthermore, since the oxide semiconductor layer 18 has a band gap ofapproximately 3.0 eV to approximately 3.5 eV, leakage photoelectriccurrent with respect to visible light is not generated. Accordingly, aninstantaneous afterimage of an oxide thin-film transistor may beprevented, making it unnecessary to form a light blocking layer underthe oxide thin-film transistor.

In order to enhance properties of the oxide semiconductor layer 18, aGroup 3, Group 4, Group 5, or transition element from the periodic tablemay be additionally included. Furthermore, although the majority of theoxide semiconductor layer 18 is an amorphous state, the oxidesemiconductor layer 18 has high effective charge mobility, and existingmanufacturing processes for amorphous silicon may be used without anychange, such that application to large display devices is possible.

The semiconductor layer 18 can be degraded by light emitted from theorganic light-emitting layer. Therefore, as will be described later, thelight-blocking layer 28 may further be formed on the pixel defininglayer 26 in the organic light-emitting display according to the currentembodiment. The light-blocking layer 28 can reduce or minimize thedegradation of the semiconductor layer 18 caused by light emitted fromthe organic light-emitting layer and improve the elemental reliabilityof the oxide semiconductor layer 18.

An additional insulating film 20 may be provided on the semiconductorlayer 18.

The source and drain electrode 24 is formed on the semiconductor layer18. An end of the source and drain electrode 24 is in contact with thesemiconductor layer 18 through a contact hole formed in the insulatingfilm 20, and the other end of the source and drain electrode 24 isconnected to the transparent electrode 12 of the pixel region P by acontact hole. As described above, when the semiconductor layer 18becomes a conductor, the source and drain electrode 24 applies a drivingvoltage to the transparent electrode 12 of the pixel region P.

The source and drain electrode 24 may be made of any one materialselected from Mo, Cr, W, MoW, Al, Al—Nd, Ti, TiN, Cu, a Mo alloy, an Alalloy, and a Cu alloy.

The pixel defining layer 26 is formed on the source and drain electrode24 to cover the source and drain electrode 24 and protect the internalcomponents. The open portion or opening O exposing a central portion ofthe transparent electrode 24 of the pixel region P or the entire portionof the transparent electrode 24 is formed in the pixel defining layer 26to define a pixel on the pixel region P.

The pixel defining layer 26 may be made of one or more organic materialsselected from a photosensitive polyimide (PSPI) material, an acrylicmaterial, a siloxane material and a novolac material, or an inorganicmaterial such as SiOx or SiNx.

Unlike in a conventional organic light-emitting display shown in FIG. 1,in the organic light-emitting display according to the currentembodiment, the light-blocking layer 28 having the open portion O isdisposed on the pixel defining layer 26. The light-blocking layer 28 isformed at the same location as the pixel defining layer 26.

As described above, the semiconductor layer 18, particularly when madeof an oxide, may be degraded by the organic light-emitting layer.Accordingly, the elemental reliability of the semiconductor layer 18 maydeteriorate, and the quality of the semiconductor layer 18 may beadversely affected. For this reason, in the organic light-emittingdisplay according to the current embodiment, the light-blocking layer 28is further formed on the pixel defining layer 26 to block lighttransmitted from the outside or light emitted by the organiclight-emitting layer, thereby minimize or reduce the degradation of thesemiconductor layer 18.

The light-blocking layer 28 according to the current embodiment may bemade of the same or different material as the pixel defining layer 26.However, the material that forms the light-blocking layer 28 shouldsatisfy properties of the pixel defining layer 26, such as dielectric,heat resistant and chemical resistant properties. That is, if thelight-blocking layer 28 formed on the pixel defining layer 26 has ahigher dielectric constant than the pixel defining layer 26, it mayaffect electrical properties of the organic light-emitting layer, thuscausing defects.

Therefore, the light-blocking layer 28 according to the currentembodiment may be made of a material with a dielectric constant of about3.0 or less. In this case, the light-blocking layer 28 may not affectthe electrical properties of the adjacent organic light-emitting layer,thus reducing defects. The light-blocking layer 28 may also be made of aheat resistant material that is resistant to outgassing. In addition,the light-blocking layer 28 may be made of a chemical resistant materialthat is unaffected by chemicals used in manufacturing processes, such asan etching solution.

The light-blocking layer 28 may be made of a colored material to protectthe semiconductor layer 18 by effectively blocking light. That is, sincethe colored material mostly reflects light in a corresponding wavelengthrange, it gives the light-blocking layer 28 the ability to selectivelyblock light. For example, the light-blocking layer 28 may be made of ablue material (400 nm) having an excellent light-blocking effect so asto block light in a corresponding wavelength range of about 350 nm toabout 450 nm. Alternatively, the light-blocking layer 28 may be made ofdye or pigment of various colors.

A material of a color having low brightness, that is, a material of acolor close to black has an excellent light-blocking effect. Therefore,the light-blocking layer 28 may be made of a material having lowbrightness in a Munsell color system. In particular, a material having abrightness of about 3 or less shows an excellent light-blocking effect.

As described above, in the organic light-emitting display according tothe current embodiment, the light-blocking layer 28 is further formed onthe pixel defining layer 26. The light-blocking effect provided by thelight-blocking layer 28 minimize the degradation of the semiconductorlayer 18 and a resulting reduction in the reliability of thesemiconductor layer 18.

The organic light-emitting layer (not shown) which emits light by itselfwhen supplied with a current is formed on the transparent electrode 12of the pixel region P. To minimize the effect that the light-blockinglayer 28 has on the organic light-emitting layer when directlycontacting the organic light-emitting layer, ends of the light-blockinglayer 28 may be situated further away from the center of the openportion O than those of the pixel defining layer 26, as shown in FIG. 2.That is, the pixel defining layer 26 may protrude further toward thecenter of the open portion O than the light-blocking layer 28 to formthe open portion O having a relatively smaller diameter. Therefore, theorganic light-emitting layer provided on the transparent electrode 12 ofthe pixel region P is separated from the light-blocking layer 28 so thatit does not directly contact the light-blocking layer 28.

Hereinafter, a method of manufacturing an organic light-emitting displayaccording to an embodiment of the present invention will be describedwith reference to FIGS. 3 through 10. FIGS. 3 through 9 arecross-sectional views sequentially illustrating a method ofmanufacturing an organic light-emitting display according to anembodiment of the present invention. FIG. 10 is a flowchart illustratinga process of forming a pixel defining layer and a light-blocking layerin an organic light-emitting display according to an embodiment of thepresent invention.

Referring to FIG. 3, transparent electrodes 12 are formed on a substrate10. As described above, the substrate 10 can be partitioned into a pixelregion P, a transistor region T and a capacitor region C. Differentcomponents are stacked on each of the pixel region P, the transistorregion T and the capacitor region C of the substrate 10, thereby forminga pixel unit, a transistor unit, and a capacitor unit.

Referring to FIG. 4, gate electrodes 14 are formed on the transistorregion T and the capacitor region C. The gate electrode 14 of thetransistor region T receives a gate voltage to control the driving of atransistor. The gate electrode 14 of the capacitor region C enables avoltage of the transistor to remain constant without a drop while thegate voltage is applied.

Referring to FIG. 5, a gate insulating film 16 is provided on the entireregion of the substrate 10 to protect the gate electrodes 14, and asemiconductor layer 18 is formed on the gate insulating film 16 of thetransistor region T. As described above, the semiconductor layer 18 maybe made of an oxide selected from ZnO, InZnO, InGaO, InSnO, ZnSnO,GaSnO, GaZnO, GaZnSnO, and GaInZnO.

Referring to FIG. 6, an insulating film 20 for protecting thesemiconductor layer 18 is formed above the substrate 10, and a facingelectrode 22 facing the above-described gate electrode 14 of thecapacitor region C is formed above the capacitor region C to maintain aconstant voltage.

Referring to FIG. 7, an open portion O is formed to expose thetransparent electrode 12 of the pixel region P. To form the open portionO, a conventional patterning process such as a wet-etching process or adry-etching process may be used. Next, a source and drain electrode 24is formed such that a first end of the source and drain electrode 24 isconnected to the semiconductor layer 18 of the transistor region T by acontact hole and a second end of the source and drain electrode 24 isconnected to the transparent electrode 12 of the pixel region P by acontact hole. The second end of the source and drain electrode 24 isconnected to an end of the transparent electrode 12 of the pixel regionP and does not overlap the open portion O. Thus, the second end of thesource and drain electrode 24 does not affect the pixel unit.

Referring to FIG. 8, a pixel defining layer 26 is provided on thesubstrate 10. As described above, the pixel defining layer 26 is formedon the entire region of the substrate 10, excluding the open portion Owhich exposes part or all the transparent electrode 12 of the pixelregion P. Thus, the pixel defining layer 26 protects the internalcomponents. In FIG. 8, the pixel defining layer 26 has a tapered edgewhich is rounded gradually from the capacitor region C toward the pixelregion P. However, the present invention is not limited thereto. Thepixel defining layer 26 can have any shape as long as its open portion Ohas a smaller diameter than that of a light-blocking layer 28.

Referring to FIG. 9, the light-blocking layer 28 is formed on the pixeldefining layer 26. The light-blocking layer 28 is situated further backthan the pixel defining layer 26 in order to not directly contact anorganic light-emitting layer. The light-blocking layer 28 may be made ofthe same material as the pixel defining layer 26. However, thelight-blocking layer 28 may be colored with dyes or pigments to be ableto block light.

Referring to FIG. 10, the process of forming the pixel defining layer 26and the light-blocking layer 28 is sequentially specified. That is, amaterial for forming the pixel defining layer 26 is coated on the entiresurface of the substrate 10 (operation S110). Then, the coated materialis solidified by a soft-bake process to form the solid pixel defininglayer 26.

Next, a conventional photolithography process using photoresist may beperformed to form the open portion O which exposes the transparentelectrode 12 of the pixel region P. If the pixel defining layer 26 ismade of a photosensitive material, it may be directly exposed to lightwithout using photoresist and then developed, thereby forming the openportion O (operation S120). After the development process, a hard-bakeprocess may further be performed.

Next, the light-blocking layer 28 is formed on the pixel defining layer26 (operation S130). Specifically, a material colored with dyes orpigments may be coated on the pixel defining layer 26 and then patternedin the same way as described above. Instead of forming thelight-blocking layer 28 by performing exposure and development processesafter the coating process, dyes or pigments having a light-blockingeffect may be inkjet-printed on the pixel defining layer 26 to form thepatterned light-blocking layer 28 on the pixel defining layer 26. If thelight-blocking layer 28 is formed using such a printing technique, theproblem of residues of, e.g., a coloring agent can be solved.

Next, the organic light-emitting layer is formed in the open portion Oformed by the above patterning process (operation S140).

Hereinafter, an organic light-emitting display according to anotherembodiment of the present invention will be described with reference toFIG. 11. FIG. 11 is a schematic cross-sectional view of an organiclight-emitting display according to another embodiment of the presentinvention.

The organic light-emitting display according to the current embodimentincludes a substrate 10 having a pixel region P and a transistor regionT, a transparent electrode 12 formed on each of the pixel region P andthe transistor region T of the substrate 10, a gate electrode 14 formedon the transparent electrode 12 of the transistor region T, a gateinsulating film 16 formed on the gate electrode 14, a semiconductorlayer 18 formed on the gate insulating film 16 of the transistor regionT, a source and drain electrode 24 having an end connected to thesemiconductor layer 18 and the other end connected to the transparentelectrode 12 of the pixel region P, a first pixel defining layer 26disposed on the source and drain electrode 24 to cover the source anddrain electrode 24 and having an open portion O which exposes thetransparent electrode 12 of the pixel region P to define the pixelregion P, a light-blocking layer 28 formed on the first pixel defininglayer 26 in the same pattern as the first pixel defining layer 26, asecond pixel defining layer 30 formed on the first pixel defining layer26 and the light-blocking layer 28, and an organic light-emitting layerformed on the transparent electrode 12 of the pixel region P. Ends ofthe light-blocking layer 28 are situated further away from the center ofthe open portion O than those of the first and second pixel defininglayers 26 and 30.

The basic configuration of the organic light-emitting display accordingto the current embodiment is the same as that of the organiclight-emitting display according to the previous embodiment, and thusany repetitive description thereof is omitted. However, the organiclight-emitting display according to the current embodiment furtherincludes the second pixel defining layer 30 on the light-blocking layer28, in addition to the components of the organic light-emitting displayaccording to the previous embodiment.

The first pixel defining layer 26 and the second pixel defining layer 30may be made of the same material. As described above, the first pixeldefining layer 26 and the second pixel defining layer 30 may be made ofone or more materials selected from a photosensitive polyimide material,an acrylic material, a siloxane material and a novolac material, or aninorganic material such as SiOX or SiNx.

The light-blocking layer 28 is interposed between the first and secondpixel defining layers 26 and 30. The material that forms thelight-blocking layer 28 is as described above. The ends of thelight-blocking layer 28 are situated further away from the center of theopen portion O than those of the first and second pixel defining layers26 and 30. Therefore, the light-blocking layer 28 does not directlycontact the organic light-emitting layer disposed on the transparentelectrode 12 of the pixel region P.

Hereinafter, a method of manufacturing an organic light-emitting displayaccording to another embodiment of the present invention will bedescribed with reference to FIGS. 12 through 15. FIGS. 12 through 14 arecross-sectional views sequentially illustrating a method ofmanufacturing an organic light-emitting display according to anotherembodiment of the present invention. FIG. 15 is a flowchart illustratinga process of forming first and second pixel defining layers and alight-blocking layer in an organic light-emitting display according toanother embodiment of the present invention.

Referring to FIG. 12, a first pixel defied layer 26 is formed on asource and drain electrode 24. Since previous processes are identical tothose of the previous embodiment, a repetitive description thereof isomitted. Unlike in the previous embodiment, a double pixel defininglayer is formed in the current embodiment. Therefore, each of the firstand second pixel defining layers 26 and 30 may be thinner than the pixeldefining layer 26 according to the previous embodiment.

Referring to FIG. 13, a light-blocking layer 28 is further formed on thefirst pixel defining layer 26. Since a double pixel defining layer isformed in the current embodiment, the light-blocking layer 28 may alsobe formed thinner than the light-blocking layer 28 according to theprevious embodiment in order to prevent the organic light-emittingdisplay from becoming excessively thick. To maximize the light-blockingeffect, the light-blocking layer 28 may be made of a black material witha dielectric constant of about 3.0 or less and excellent heat resistantand chemical resistant properties. As described above, thelight-blocking layer 28 is situated further away from an open portion Othan the first pixel defining layer 26 by a predetermined distance.Accordingly, the light-blocking layer 28 does not directly contact anorganic light-emitting layer and thus does not deteriorate electricalproperties of the organic light-emitting layer.

Referring to FIG. 14, the second pixel defining layer 30 is formed onthe light-blocking layer 28. Like the first pixel defining layer 26, thesecond pixel defining layer 30 protrudes further toward the open portionO than the light-blocking layer 28 thereunder, thereby preventing thelight-blocking layer 28 from being exposed in the open portion O.

Referring to FIG. 15, the first pixel defining layer 26 is coated(operation S210) and then exposed to light and developed to form theopen portion O (operation S220). Then, the light-blocking layer 28 isformed on the first pixel defining layer 26 (operation S230). Asdescribed above, the light-blocking layer 28 may be coated on thesurface of the first pixel defining layer 26 and then patterned using aphotolithography process to form the open portion O. Alternatively,light-blocking dyes may be inkjet-printed to directly pattern thelight-blocking layer 28.

After the formation of the light-blocking layer 28, the second pixeldefining layer 30 is formed on the light-blocking layer 28. The secondpixel defining layer 30 may be formed in the same way as the first pixeldefining layer 26 (operations S240 and 250). Next, the organiclight-emitting layer is formed in the open portion O (operation S260).

In organic light-emitting displays and methods of manufacturing the sameaccording to embodiments of the present invention, it is possible tominimize the degradation of an oxide semiconductor layer caused byinternal light which is emitted from a light-emitting layer or externallight. Therefore, the elemental reliability of the oxide semiconductorlayer can be improved.

While the present invention has been particularly shown and describedwith reference to embodiments thereof, it will be understood by those ofordinary skill in the art that various changes in form and detail may bemade therein without departing from the spirit and scope of the presentinvention as defined by the following claims. The embodiments should beconsidered in a descriptive sense only and not for purposes oflimitation.

What is claimed is:
 1. A method of manufacturing an organiclight-emitting display, the method comprising: providing a structurecomprising a substrate having a pixel region and a transistor region,the structure further comprising a first electrode in the pixel regionand a transistor in the transistor region; forming a pixel defininglayer over the transistor region while exposing at least a portion ofthe first electrode; forming a light-blocking layer over at least partof the pixel defining layer; and forming an organic light-emitting layerover the exposed portion of the first electrode.
 2. The method of claim1, wherein the transistor comprises: a gate electrode, a gate insulator,a channel, a source and a drain, wherein the gate electrode isinterposed between the gate insulator and the substrate, wherein thesource is electrically connected to the first electrode.
 3. A method ofmanufacturing an organic light-emitting display, the method comprising:providing a structure comprising a substrate having a pixel region and atransistor region, the structure further comprising a first electrode inthe pixel region and a transistor in the transistor region; forming apixel defining layer over the transistor region while exposing at leasta portion of the first electrode; forming a light-blocking layer over atleast part of the pixel defining layer; and forming an organiclight-emitting layer over the exposed portion of the first electrode,wherein the transistor comprises: a gate electrode, a gate insulator, achannel, a source and a drain, wherein the gate electrode is interposedbetween the gate insulator and the substrate, wherein the source iselectrically connected to the first electrode, and wherein providing thestructure comprises: foaming a second electrode over the transistorregion at the same level as the first electrode; forming the gateelectrode over the second electrode; forming a semiconductor layercomprising an oxide over the gate electrode; and forming the channel,source and drain in the semiconductor layer.
 4. The method of claim 1,wherein forming the pixel defining layer comprises: forming a layer of amaterial for the pixel defining layer over the first electrode andfurther over the transistor; and creating an opening in the layer of thematerial for the pixel defining layer to expose the portion of the firstelectrode.
 5. The method of claim 1, wherein forming the pixel defininglayer comprises exposing an open portion of the pixel defining layer tolight and developing the open portion.
 6. The method of claim 1, whereinforming the light-blocking layer comprises forming an opening of thelight-blocking layer disposed over the first transparent electrode suchthat a boundary of the opening of the light-blocking layer is situatedfurther away from a center of an opening of the pixel defining layercompared to a boundary of an opening of the pixel defining layer.
 7. Themethod of claim 1, wherein the pixel defining layer is made of one ormore materials selected from the group consisting of a photosensitivepolyimide material, an acrylic material, a siloxane material, and anovolac material.
 8. The method of claim 1, wherein the light-blockinglayer comprises a material with a dielectric constant of about 3.0 orless.
 9. The method of claim 1, wherein the light-blocking layercomprises a black material.
 10. The method of claim 1, wherein thelight-blocking layer is configured to block light in a wavelength rangeof about 350 nm to about 450 nm.
 11. The method of claim 1, wherein inthe forming of the light-blocking layer, a light-blocking material isinkjet-printed over a predetermined region of the substrate.
 12. Themethod of claim 1, wherein the transistor comprises an oxidesemiconductor material.
 13. A method of manufacturing an organiclight-emitting display, the method comprising: providing a structurecomprising a substrate having a pixel region and a transistor region,the structure further comprising a first electrode in the pixel regionand a transistor in the transistor region; forming a first pixeldefining layer over the transistor region while exposing at least aportion of the first electrode; forming a light-blocking layer over atleast part of the first pixel defining layer; forming a second pixeldefining layer over at least part of the light-blocking layer whileexposing the at least a portion of the first electrode; and forming anorganic light-emitting layer over at least part of the exposed portionof the first electrode.
 14. The method of claim 13, wherein thetransistor comprises: a gate electrode, a gate insulator, a channel, asource and a drain, wherein the gate electrode is interposed between thegate insulator and the substrate, wherein the source is electricallyconnected to the first electrode.
 15. The method of claim 14, whereinproviding the structure comprises: forming a second electrode over thetransistor region at the same level as the first electrode; forming thegate electrode over the second electrode; forming a semiconductor layercomprising an oxide over the gate electrode; and forming the channel,source and drain in the semiconductor layer.
 16. The method of claim 13,wherein forming the first pixel defining layer comprises: forming alayer of a material for the first pixel defining layer over the firstelectrode and further over the transistor; and creating an opening inthe layer of the material for the first pixel defining layer to exposethe at least a portion of the first electrode.
 17. The method of claim13, wherein the forming the first pixel defining layer of exposing anopen portion of the first pixel defining layer to light and developingthe open portion.
 18. The method of claim 13, wherein in the forming thelight-blocking layer comprises inkjet-printing a light-blocking materialover a predetermined region of the substrate.
 19. The method of claim13, wherein the first and second pixel defining layers comprise one ormore materials selected from the group consisting of a photosensitivepolyimide material, an acrylic material, a siloxane material, and anovolac material.
 20. The method of claim 19, wherein the first andsecond pixel defining layers comprise the same material.
 21. The methodof claim 13, wherein the transistor comprises an oxide semiconductormaterial.